Syrian government forces had deployed in Sweida city in the country's south on Tuesday, clashing with Druze fighters who previously controlled the area.

State television reported on Wednesday afternoon "a new aggression by the Israeli occupation air force in Umayyad Square, near the (military) headquarters building in central Damascus".

A live broadcast by the Qatari channel Al Jazeera showed a series of air strikes on the headquarters, with smoke billowing into the sky and parts of the building damaged.

State television had reported an earlier strike near the headquarters, which Israel's military said it had attacked.

The Syrian health ministry said in a preliminary toll that nine people were wounded by the strikes.

Israeli Defence Minister Israel Katz had warned on Wednesday that his country would start launching major attacks against Syria.

"The signals to Damascus are over -- now come the painful blows," he said.

The Israeli military would "operate forcefully" in Syria's southern Sweida region "to eliminate the forces that attacked the Druze until their full withdrawal", he added.